The present invention relates to radio frequency identification (RFID) systems, and is particularly directed to an RFID tag and a method of operating an RFID tag.
RFID tags and their construction and operation are well known. A typical RFID tag includes RFID circuitry and an antenna by which signals are received from or transmitted to an RFID reader located within the operating range of the RFID tag. During operation, the RFID circuitry receives a signal communicated from the RFID reader and generates a signal which is communicated back to the RFID reader.
In some RFID tag applications, there is usually more than one RFID tag generating its signal which is communicated back to the RFID reader. Since multiple signals are being communicated back to the RFID reader, collisions may occur resulting in potential data loss. Anticollision techniques have been applied to differentiate between signals received from two or more RFID tags. A drawback in known anticollision techniques is that signals from only a limited number of different RFID tags can be differentiated.
It would be desirable to be able to differentiate signals received from a relatively large number of RFID tags which are located within a limited physical area and within the operating range of the RFID reader. For example, it would be desirable to differentiate signals received from RFID tags contained in a relatively large stack of bank checks in which each bank check has a corresponding RFID tag associated therewith.